Automobile low-voltage wire harness incomplete short circuit protection method and system

Abstract

The invention discloses an automobile low-voltage wire harness incomplete short circuit protection method and system, and belongs to the field of automobile safety. The method comprises the steps of detecting discharge current of the battery pack; obtaining and accumulating independent required current of each low-voltage wire harness loop, and taking an accumulation result as total required current; subtracting the discharge current from the total demand current, and comparing the difference value with a preset difference threshold value; if the difference value is greater than or equal to a preset difference threshold value, calculating the maximum current value of each low-voltage wire harness loop; based on a preset current-smoking time curve, whether the wiring harness has a smoking risk or not is judged, and when the smoking risk exists, the smoking time corresponding to the maximum current value of each low-voltage wiring harness loop is obtained; and according to the smoking time, controlling the on-off of the fuse of the low-voltage wire harness fuse box of the whole vehicle. According to the invention, the safety of the low-voltage wire harness of the whole vehicle is improved, and the low-voltage wire harness electrical fault caused by low overload of the low-voltage wire harness of the vehicle is avoided, so that the safety of the whole vehicle is improved.

Description

Technical Field

[0001] The present invention belongs to the field of automotive safety. Specifically, the present invention relates to a method and system for protecting an automotive low-voltage wiring harness against incomplete short circuits. Background Art

[0002] Since automotive electrical appliances are distributed throughout the vehicle, the wiring harness, as the power supply medium, needs to pass through sheet metal holes. Rubber parts, as connectors, need to have the functions of waterproofing, sealing, dustproofing, and protecting the wiring harness. However, direct outgoing wires are prone to water ingress and interference wear with the surrounding, resulting in a short circuit of the wiring harness, thus leading to safety risks and having high requirements for the wiring harness processing technology.

[0003] In order to protect the safety of the wiring harness, in the prior art, a main fuse is usually installed. However, since the main fuse needs to take into account the discharge capacity of all electrical appliances, the fuse specification selection is relatively large. This type of fuse can only protect against complete short circuits and cannot effectively protect against slight contact short circuits, and is prone to overloading, overheating, and even catching fire. Due to the large difference between the rated power and the maximum power of the load, and the situation where multiple loads work simultaneously, in order to cope with extreme working conditions, the main circuit wiring harness often needs to adopt a higher configuration (larger wire diameter), which will also increase the weight and cost of the whole vehicle.

[0004] In view of the above situation, if fuses are configured on all circuits of large and small loads or auxiliary devices such as temperature sensors are added to monitor current overload, not only the cost cannot be reduced, but the actual layout operation is very difficult, and the wiring harness layout size also needs to be increased.

[0005] Therefore, the present invention proposes a method and system for protecting an automotive low-voltage wiring harness against incomplete short circuits. Summary of the Invention

[0006] The present invention aims to overcome the deficiencies of the prior art and proposes a method and system for protecting an automotive low-voltage wiring harness against incomplete short circuits to achieve the following objectives: improving the safety of the whole vehicle's low-voltage wiring harness, avoiding electrical faults of the low-voltage wiring harness caused by low overload of the automotive low-voltage wiring harness, and thus effectively improving the safety of the whole vehicle.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for protecting an automotive low-voltage wiring harness against incomplete short circuits, the method comprising the following steps:

[0008] Step S1, real-time detecting the current discharge current of the battery pack;

[0009] Step S2, obtaining the current individual demand currents of each low-voltage wiring harness circuit and accumulating them, and the accumulated result is used as the total demand current;

[0010] Step S3, subtracting the current discharge current from the total demand current, and comparing the obtained difference with a preset difference threshold;

[0011] Step S4. If the difference is less than a preset difference threshold, return to Step S1; if the difference is greater than or equal to the preset difference threshold, calculate the maximum current value of each low-voltage harness circuit.

[0012] Step S5. Based on a preset current-smoke time curve, determine whether there is a risk of the harness smoking, and when there is a risk of smoking, obtain the smoke time corresponding to the maximum current value of each low-voltage harness circuit, where the smoke time represents the time required for the harness to smoke at the corresponding current.

[0013] Step S6. Control the on / off of the fuses in the vehicle's low-voltage harness fuse box according to the smoke time.

[0014] Preferably, in Step S2, obtain the power required by the loads of each low-voltage harness circuit through the in-vehicle network bus, and obtain the current individual demand of each low-voltage harness circuit according to the power.

[0015] Preferably, in Step S4, the method for calculating the maximum current value of each low-voltage harness circuit is: add the current individual demand of each low-voltage harness circuit to the difference respectively, so as to obtain the maximum current value of each low-voltage harness circuit respectively.

[0016] Preferably, in Step S5, if there is no risk of smoking, only record the current overlimit fault and return to Step S1 for continuous monitoring.

[0017] Preferably, in Step S6, if the smoke time is greater than a preset time threshold, only mark the circuit fault and record the smoke time; if the smoke time is less than or equal to the preset time threshold, immediately control the fuse in the vehicle's low-voltage harness fuse box to disconnect, and output an alarm message and report the fault.

[0018] Preferably, in Step S6, the control of the on / off of the fuses in the vehicle's low-voltage harness fuse box is also determined by the current vehicle speed, that is: when the smoke time is less than or equal to the preset time threshold, if the current vehicle speed is not 0, delay the control of the fuse in the vehicle's low-voltage harness fuse box to disconnect; if the current vehicle speed is 0, immediately control the fuse in the vehicle's low-voltage harness fuse box to disconnect.

[0019] Meanwhile, the present application also proposes an incomplete short-circuit protection system for an automotive low-voltage harness. The system includes an intelligent electrical box, a first controller, a memory, and a vehicle's low-voltage harness fuse box. The intelligent electrical box is connected to the first controller; the first controller is connected to the vehicle's low-voltage harness fuse box; the memory is connected to the first controller, where:

[0020] The intelligent electrical appliance box is used to detect the current discharge current of the battery pack in real time, obtain the total required current of each low-voltage wire harness loop, and send it to the first controller;

[0021] The first controller is used to send a control signal to the vehicle low-voltage wire harness fuse box according to the method described in any one of claims 1-6;

[0022] The vehicle low-voltage wire harness fuse box is used to execute the on / off of the fuse according to the control signal of the first controller;

[0023] The memory is used to record fault information and stores a preset current-smoke time curve for the first controller to call.

[0024] Preferably, the intelligent electrical appliance box includes a second controller, a current sampling circuit, and a communication unit. The second controller is respectively connected to the current sampling circuit, the communication unit, and the first controller. Among them, the current sampling circuit is used to collect the discharge current of the battery pack and send it to the second controller; the communication unit is used to communicate with the loads in each low-voltage wire harness loop through the vehicle network to obtain the required power and send it to the second controller; the second controller is used to calculate the total required current of each low-voltage wire harness loop according to the required power and send it to the first controller together with the discharge current of the battery pack.

[0025] Preferably, the communication unit includes a CAN transceiver, and the second controller communicates with the vehicle CAN network through the CAN transceiver.

[0026] Preferably, both the first and second controllers adopt a microcontroller MCU.

[0027] The technical effects of the present invention are as follows:

[0028] (1) The present invention dynamically calculates the total required current through the battery pack discharge current and the required power of each low-voltage wire harness loop, realizes real-time tracking of current data, and reduces the wire harness layout cost compared with the traditional external sensor scheme.

[0029] (2) The present invention uses the difference between the battery pack discharge current and the total required current as a fault criterion, and the threshold setting can be flexibly adapted to different wire harness scenarios. When the difference exceeds the limit, the fault judgment is triggered, and the sensitivity is higher.

[0030] (3) The present invention calculates the smoke time based on the preset current-smoke time curve, ensuring the reliability of the smoke time.

[0031] (4) The present invention controls the on / off of the fuse of the vehicle low-voltage wire harness fuse box according to two influencing factors, the smoke time and the vehicle speed, which is more suitable for the actual application scenario and further ensures the safety of the whole vehicle. Description of the Drawings

[0032] Figure 1 Flow chart of a method for protecting an automotive low - voltage harness against incomplete short - circuit according to an embodiment of the present invention;

[0033] Figure 2 Schematic structural diagram of a system for protecting an automotive low - voltage harness against incomplete short - circuit according to an embodiment of the present invention. Detailed implementation manners

[0034] The following describes in further detail the specific implementation manners of the present invention by referring to the accompanying drawings and through the description of the embodiments, aiming to help those skilled in the art have a more complete, accurate and in - depth understanding of the inventive concept and technical solutions of the present invention and facilitate its implementation. It should be noted that the terms "first", "second", etc. used in this application are only for conveniently describing the technical solutions to distinguish different components, and do not limit this application. To make the technical solutions of the present invention clearer, the present invention is explained and illustrated through the following embodiments.

[0035] This embodiment provides a method for protecting an automotive low - voltage harness against incomplete short - circuit. The method of this embodiment is specifically described below in combination with the Figure 1 method flow as shown.

[0036] Step S1: Real - time detect the current discharge current of the battery pack.

[0037] The power consumption of the vehicle's low - voltage load is provided by the vehicle's battery pack, and they are connected through the vehicle's low - voltage harness. By detecting the current discharge current of the battery pack, the real - time working current on the current vehicle harness can be obtained. The battery pack often uses a low - voltage storage battery, and at the same time, a power battery pack can also be used, but the output of the power battery needs to be stepped down before use.

[0038] Step S2: Obtain the current individual demand currents of each low - voltage harness loop and accumulate them, and the accumulated result is used as the total demand current.

[0039] In the prior art, when the load in the low - voltage harness loop is working, it will request power matching from the vehicle controller or body controller through the built - in ECU (Electronic Control Unit). Among them, the commonly used communication method is CAN network communication. Therefore, in this embodiment, the power required by the loads in each low - voltage harness loop can be obtained through the in - vehicle network bus. In this way, on the premise that the power is known, the current individual demand currents of each low - voltage harness loop can be calculated according to the power. The commonly used formula is: I=(P / R) 1 / 2, where I represents current, P represents power, and R represents resistance. By obtaining power through the vehicle network bus and then calculating the current, the actual requirements of each circuit are dynamically tracked, ensuring the real-time nature of data collection, thereby improving the subsequent speed of harness fault judgment to enable timely handling in case of faults.

[0040] Step S3: Subtract the current discharge current from the total demand current, and compare the obtained difference with a preset difference threshold.

[0041] Under normal circumstances in the low-voltage harness circuit, the error between the discharge current of the battery pack and the total demand current will not be too large and should be at a basically consistent level. However, when the low-voltage harness of any low-voltage harness circuit is short-circuited due to accidental situations such as water ingress or wear, the actual discharge current of the battery pack will increase sharply. Therefore, based on this, in this embodiment, the current discharge current is subtracted from the total demand current, and the obtained difference is compared with a preset difference threshold to determine whether the voltage harness has a short-circuit fault. Compared with the traditional method of setting external sensors in each low-voltage harness circuit to monitor in real time whether there is current overload, no additional harness layout is required, reducing costs.

[0042] Step S4: If the difference is less than the preset difference threshold, return to Step S1; if the difference is greater than or equal to the preset difference threshold, calculate the maximum current value of each low-voltage harness circuit.

[0043] To ensure the rapid response of fault judgment and at the same time support flexible adjustment and adaptation to multiple scenarios, in this embodiment, fault judgment is performed by setting a difference threshold. The difference threshold can be flexibly selected according to the actual situation during specific implementation to adapt to different low-voltage harnesses. If the difference is less than the preset difference threshold, it is regarded as no fault; if the difference is greater than or equal to the preset difference threshold, it is regarded as a fault occurring.

[0044] In this embodiment, the calculation method for the maximum current value of each low-voltage harness circuit is as follows: Add the current individual demand current of each low-voltage harness circuit to the difference respectively to obtain the maximum current value of each low-voltage harness circuit. In this way, it is defaulted that the low-voltage harness fault may occur in each low-voltage harness circuit, avoiding misjudgment and missed judgment.

[0045] Step S5: Based on a preset current-smoking time curve, determine whether the harness has a smoking risk, and when there is a smoking risk, obtain the smoking time corresponding to the maximum current value of each low-voltage harness circuit. The smoking time represents the time required for the harness to smoke at the corresponding current.

[0046] In this embodiment, the current-smoking time curve is obtained in advance through a large number of experiments. To ensure the reliability of the current-smoking time curve, the experiment can set low-voltage wiring harnesses with different resistances and measure the time required for smoking under different current impacts. This embodiment also pre-judges whether the wiring harness has a smoking risk according to the current-smoking time curve. If the current on the actual low-voltage wiring harness loop is not within the preset current-smoking time curve, or the smoking time is infinite within the preset current-smoking time curve, it is regarded as having no smoking risk. On the premise of no smoking risk, this embodiment only records the current overlimit fault and returns to the step S1 for continuous monitoring. At the same time, the smoking time is calculated based on the preset current-smoking time curve, ensuring the reliability of the smoking time.

[0047] Step S6: Control the on-off of the fuse in the vehicle's low-voltage wiring harness fuse box according to the smoking time.

[0048] When there is a smoking risk, the on-off control of the fuse in the vehicle's low-voltage wiring harness fuse box is determined by the smoking time. Specifically, if the smoking time is greater than the preset time threshold, it means that the smoking time is within the acceptable range of the user and will not cause a safety risk, then only mark the circuit fault and record the smoking time to facilitate later maintenance; if the smoking time is less than or equal to the preset time threshold, it means that the low-voltage wiring harness has smoked or is about to smoke due to a short circuit of the wiring harness, with a great safety risk, then immediately control the fuse in the vehicle's low-voltage wiring harness fuse box to disconnect, and output an alarm message and report the fault, thereby effectively improving the safety of the vehicle. In specific implementation, the preset time threshold can be flexibly selected according to the actual situation.

[0049] Furthermore, the on-off control of the fuse in the vehicle's low-voltage wiring harness fuse box in this embodiment is also determined by the current vehicle speed, that is: when the smoking time is less than or equal to the preset time threshold, if the current vehicle speed is not 0, then delay the control of the fuse in the vehicle's low-voltage wiring harness fuse box to disconnect, and the delay time can be flexibly selected according to the actual situation; if the current vehicle speed is 0, then immediately control the fuse in the vehicle's low-voltage wiring harness fuse box to disconnect. When the vehicle speed is not 0, it means that the vehicle is in a driving state. If the low-voltage wiring harness fuse is immediately disconnected at this time, it may cause problems such as the driver panicking and the vehicle control system malfunctioning, and then lead to secondary hazards such as vehicle collisions and endanger the safety of the vehicle and personnel. When the vehicle speed is 0, it means that the vehicle is in a stationary state. At this time, the vehicle can be immediately powered down to ensure the safety of the vehicle and personnel in a timely manner.

[0050] In addition, this embodiment also proposes an incomplete short-circuit protection system for the vehicle's low-voltage wiring harness according to the above method, such as Figure 2As shown, the system includes an intelligent electrical box, a first controller, a memory, and a vehicle low-voltage wire harness fuse box. The intelligent electrical box is connected to the first controller; the first controller is connected to the vehicle low-voltage wire harness fuse box; the memory is connected to the first controller, where:

[0051] The intelligent electrical box is used to detect the current discharge current of the battery pack in real time, obtain the total required current of each low-voltage wire harness circuit, and send it to the first controller;

[0052] The first controller is used to judge the low-voltage wire harness fault according to the method of this embodiment and send a control signal to the vehicle low-voltage wire harness fuse box;

[0053] The vehicle low-voltage wire harness fuse box is used to execute the on / off of the low-voltage wire harness fuse according to the control signal of the first controller;

[0054] The memory is used to record various fault information and stores a preset current-smoke time curve for the first controller to call.

[0055] Specifically, the intelligent electrical box of this embodiment includes a second controller, a current sampling circuit, and a communication unit. The second controller is respectively connected to the current sampling circuit, the communication unit, and the first controller. Among them, the current sampling circuit is used to collect the discharge current of the battery pack and send it to the second controller; the communication unit is used to communicate with the loads in each low-voltage wire harness circuit through the in-vehicle network to obtain the required power and send it to the second controller; the second controller is used to calculate the total required current of each low-voltage wire harness circuit according to the required power and send it to the first controller together with the discharge current of the battery pack.

[0056] Since in existing vehicles, in-vehicle CAN network is generally used for communication between various ECUs in the vehicle, the communication unit of this embodiment includes a CAN transceiver, and the second controller communicates with the in-vehicle CAN network through the CAN transceiver. Based on the communication of the CAN network, the data transmission speed is faster and more stable, ensuring that the second controller can receive the collected data in time and send it to the first controller, thereby improving the timeliness of the first controller's fault judgment and processing.

[0057] Furthermore, the first and second controllers of this embodiment both adopt a microcontroller MCU. The microcontroller MCU has the advantages of high integration and small volume, ensuring the data processing efficiency of the first and second controllers to ensure the timeliness of fault judgment and processing, and at the same time reducing the cost.

[0058] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. A method for protecting a low-voltage wiring harness from incomplete short circuit in an automobile, characterized in that: The method comprises the following steps: Step S1, real-time detection of the current discharge current of the battery pack; Step S2, obtaining the current individual demand currents of each low-voltage wiring harness loop and accumulating them, and using the accumulated result as the total demand current; Step S3, subtracting the current discharge current from the total demand current, and comparing the obtained difference with a preset difference threshold; Step S4: if the difference is less than a preset difference threshold, return to step S1; if the difference is greater than or equal to the preset difference threshold, calculate the maximum current value of each low-voltage wiring harness loop; Step S5, judging whether the wiring harness has a risk of smoking based on a preset current-smoke time curve, and obtaining the smoke time corresponding to the maximum current value of each low-voltage wiring harness loop when there is a risk of smoking, wherein the smoke time indicates the time required for the wiring harness to smoke under the corresponding current; Step S6: Controlling the on / off of the low-voltage wiring harness fuse box of the vehicle according to the smoke time.

2. A method for protecting a low-voltage wiring harness from incomplete short circuit in an automobile according to claim 1, characterized in that: In the step S2, the power required by the load of each low-voltage wiring harness loop is obtained through the vehicle network bus, and the current individual required current of each low-voltage wiring harness loop is obtained according to the power.

3. The method for protecting a low-voltage wiring harness from incomplete short circuit in an automobile according to claim 1, characterized in that: In step S4, the maximum current value of each low-voltage wiring harness loop is calculated by adding the current individual demand current of each low-voltage wiring harness loop to the difference, thereby obtaining the maximum current value of each low-voltage wiring harness loop.

4. A method for protecting a low-voltage wiring harness from incomplete short circuit in an automobile according to claim 1, characterized in that: In step S5, if there is no risk of smoke, only the current over-limit fault is recorded and the process returns to step S1 for continuous monitoring.

5. A method for protecting a low-voltage wiring harness of an automobile from incomplete short circuit according to claim 1 or 4, characterized in that: In step S6, if the smoking time is greater than a preset time threshold, only the circuit fault is marked and the smoking time is recorded; if the smoking time is less than or equal to the preset time threshold, the low-voltage wiring harness fuse box of the entire vehicle is immediately controlled to disconnect, and an alarm message is output and the fault is reported.

6. A method for protecting a low-voltage wiring harness from incomplete short circuit in an automobile according to claim 5, characterized in that: In step S6, the control of the on / off of the low-voltage wiring harness fuse box of the whole vehicle is also determined by the current vehicle speed, that is: when the smoke time is less than or equal to the preset time threshold, if the current vehicle speed is not 0, the low-voltage wiring harness fuse box of the whole vehicle is controlled to disconnect with a delay; if the current vehicle speed is 0, the low-voltage wiring harness fuse box of the whole vehicle is immediately controlled to disconnect.

7. An automotive low-voltage wiring harness non-complete short-circuit protection system according to any one of claims 1 to 6, characterized in that: The system includes an intelligent electrical box, a first controller, a memory, and a low-voltage wiring harness fuse box for the whole vehicle. The intelligent electrical box is connected to the first controller; the first controller is connected to the low-voltage wiring harness fuse box for the whole vehicle; The memory is connected to the first controller, wherein: The intelligent electrical box is used to detect the current discharge current of the battery pack in real time and obtain the total required current of each low-voltage wiring harness circuit and send it to the first controller; The first controller is used to send a control signal to the low-voltage wiring harness fuse box of the vehicle according to the method described in any one of claims 1 to 6; The vehicle low-voltage wiring harness fuse box is used to execute the on-off of the fuse according to the control signal of the first controller; The memory is used to record fault information and store a preset current-smoke time curve for the first controller to call.

8. The automotive low-voltage wiring harness non-complete short-circuit protection system according to claim 7, characterized in that: The smart electrical box includes a second controller, a current sampling circuit, and a communication unit, wherein the second controller is connected to the current sampling circuit, the communication unit, and the first controller respectively, wherein the current sampling circuit is used to collect the discharge current of the battery pack and send it to the second controller; the communication unit is used to communicate with the loads in each low-voltage wiring harness loop through the vehicle network to obtain the required power and send it to the second controller; the second controller is used to calculate the total required current of each low-voltage wiring harness loop according to the required power, and send it to the first controller together with the discharge current of the battery pack.

9. The automotive low-voltage wiring harness non-complete short-circuit protection system according to claim 8, characterized in that: The communication unit includes a CAN transceiver, and the second controller communicates with the vehicle-mounted CAN network through the CAN transceiver.

10. An automotive low-voltage wiring harness non-complete short-circuit protection system according to claim 8 or 9, characterized in that: The first and second controllers both adopt microcontrollers MCU.

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